Monday, February 25, 2008

YouTube's disappearing act explained

On Sunday afternoon, while searching for a clip of Nicolas Sarkozy swearing at voters, I discovered that YouTube had disappeared from the face of the internet.

Contrary to early reports, it seems the site wasn't hacked, at least not deliberately. Rather, it disappeared because of an unfortunate (and presumably accidental) mix-up at a major ISP in Pakistan. Ars Technica has a good technical explanation.

The Pakistani government had just ordered the ISP in question to block access to YouTube because of offensive and "non-Islamic" videos hosted there. What engineers at the company did was add a rule to their routers that sent data destined for YouTube off nowhere in particular.

Unfortunately, this rule got forwarded to a major ISP in Hong Kong and then on to other routers around the world. And as a result, requests from users outside of Pakistan ended up being sent into the same black hole.

Should we be alarmed that such big site can be knocked out of action so easily? Well, I don't think it's a major cause for concern. After all, the problem was rapidly fixed ? Google just reassigned YouTube to a different block of IP addresses. And it would be hard for anyone to deliberately perform the same stunt more than once before other routers started ignoring them altogether.

Of course, some people might argue that being unable to access YouTube videos for a few hours is not such a bad thing. But it certainly put a dent in my afternoon.